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      <title>RabbitMQ的消息确认机制 - 交互式测验</title>
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          <div class="quiz-container">
            <div class="quiz-header">
              <h1>RabbitMQ的消息确认机制 - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
            </div>
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      <script>
        const quizData = [
  {
    "question": "在RabbitMQ的消费者确认机制中，使用“自动确认（Auto Acknowledgment）”模式可能导致的主要风险是什么？",
    "options": [
      "显著降低消息处理的吞吐量。",
      "如果消费者在处理消息时崩溃，该消息将永久丢失且无法被重新投递。",
      "导致消息在队列中被重复投递给同一个消费者。",
      "需要编写额外的代码来手动发送确认信号，增加了复杂性。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "在自动确认模式下，RabbitMQ在向消费者投递消息后会立即将其标记为已确认并从队列中删除。如果消费者在接收到消息后、业务逻辑完全处理完之前发生故障（如进程崩溃），那么这条消息就永久丢失了，因为它已经被RabbitMQ认为成功处理了。",
    "source": "文档中「Consumer消息确认机制」->「2.1 自动确认（Auto Acknowledgment）」部分",
    "hint": "文档提到，自动确认模式虽然简单，但“存在消息丢失的风险”。思考一下这种风险发生的具体场景。"
  },
  {
    "question": "根据文档，生产者的哪种消息确认模式被认为最能在可靠性和性能之间取得平衡，也是最推荐的方式？",
    "options": [
      "单条确认 (Single Message Confirm)，因为它确保每条消息都得到确认，可靠性最高。",
      "批量确认 (Batch Confirm)，因为它一次性发送一批消息，处理效率最高。",
      "异步确认 (Asynchronous Confirm)，因为它通过回调函数处理确认，不会阻塞生产者，兼顾了性能与可靠性。",
      "事务机制 (Transactional)，因为它能保证消息发送与数据库操作的原子性。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "异步确认模式允许生产者发送消息后不必等待Broker的确认，而是通过注册回调函数来处理成功（ACK）或失败（NACK）的通知。这种非阻塞的方式显著提高了发送性能，同时通过回调机制保证了消息的可靠性，因此是官方和文档中最推荐的方式。",
    "source": "文档中「Producer消息确认机制」->「1. Producer消息确认机制的概念」部分",
    "hint": "文档中明确指出有一种模式“结合了可靠性和性能的优势”，并被描述为“最推荐的方式”。"
  },
  {
    "question": "RabbitMQ的Return机制和Confirm机制有何根本区别？",
    "options": [
      "Confirm机制用于消费者，Return机制用于生产者。",
      "Confirm机制确保消息成功到达Broker，而Return机制处理消息到达Broker后但无法路由到任何队列的情况。",
      "Confirm机制是同步的，而Return机制是异步的。",
      "Return机制用于处理消息处理成功的情况，Confirm机制用于处理失败的情况。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "Confirm机制的核心目的是确认消息是否已成功从生产者发送并被RabbitMQ服务器接收。而Return机制则是一个补充，它处理的是“消息已成功到达服务器，但服务器根据路由键无法找到合适的队列进行投递”的特殊情况，此时服务器会将该消息返回给生产者。",
    "source": "文档中「Producer消息确认机制」->「5.5. Return机制与Confirm机制的对比」部分",
    "hint": "一个关注的是消息是否“到达”了Broker，另一个关注的是消息到达后是否能被成功“投递”到队列。"
  },
  {
    "question": "在什么情况下，一条消息会被发送到死信队列（DLQ）？",
    "options": [
      "消费者成功处理消息并发送了 basic.ack。",
      "生产者使用了事务机制并提交失败（tx.rollback）。",
      "消费者使用 basic.nack 拒绝了消息，并且将 requeue 参数设置为 false。",
      "消费者处理消息超时，但未向Broker发送任何确认或拒绝信号。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "将消息发送到死信队列的常见触发条件之一是消息被消费者明确拒绝。具体来说，当消费者调用 `basic.reject` 或 `basic.nack` 方法，并且将 `requeue` 参数设置为 `false` 时，RabbitMQ 就不会将该消息重新放回原队列，而是会根据配置将其路由到指定的死信队列中。",
    "source": "文档中「消息重传和死信队列」->「2.1 触发条件」部分",
    "hint": "文档中列出了三个触发条件，其中之一与消费者使用 `basic.reject` 或 `basic.nack` 拒绝消息有关。"
  },
  {
    "question": "与消息确认机制相比，RabbitMQ的事务机制一个显著的缺点是什么？",
    "options": [
      "无法保证消息的原子性。",
      "可靠性较低，容易丢失消息。",
      "对系统性能有较大影响，会显著降低消息的吞吐量。",
      "只能用于消费者端，不能用于生产者。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "事务机制为了保证操作的原子性（要么全部成功，要么全部回滚），需要Broker进行额外的状态管理和同步等待，这是阻塞性的操作。因此，在高并发场景下，开启事务会使信道进入事务模式，大大降低消息的发送速率和吞吐量，性能开销非常高。",
    "source": "文档中「事务机制与消息确认机制的对比」->「3. 性能影响」部分",
    "hint": "在“性能影响”一节中，文档直接对比了两种机制的性能开销，并指出了事务机制的性能问题。"
  },
  {
    "question": "当一个消费者在手动确认模式下处理消息时遇到临时性故障（例如外部服务暂时不可用），为了确保该消息后续能被重新处理，最恰当的操作是什么？",
    "options": [
      "调用 `channel.basicAck`，然后将消息内容记录到本地日志中以便手动恢复。",
      "调用 `channel.basicNack`，并将 `requeue` 参数设置为 `true`。",
      "什么都不做，等待连接超时，让RabbitMQ自动重发。",
      "调用 `channel.basicNack`，并将 `requeue` 参数设置为 `false`。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "对于临时性故障，我们希望消息能被重新投递给某个消费者（可能是自己或另一个）再次尝试。通过调用 `basic.nack` (或 `basic.reject`) 并将 `requeue` 参数设置为 `true`，可以明确地告知RabbitMQ处理失败，并请求将该消息重新放回队列头部，以便后续投递。",
    "source": "文档中「消息重传和死信队列」->「1.1 实现方式」部分",
    "hint": "思考一下如何告诉RabbitMQ“这次处理失败了，请把消息放回队列，稍后重试”。"
  },
  {
    "question": "在整个消息确认流程中，RabbitMQ服务器（Broker）的核心职责不包括哪一项？",
    "options": [
      "接收生产者消息并进行持久化存储。",
      "向生产者发送消息接收确认。",
      "执行消息体内的具体业务逻辑。",
      "等待并处理来自消费者的消费确认（ACK/NACK）。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "RabbitMQ服务器（Broker）是消息中间件，其核心职责是可靠地接收、存储和分发消息，并管理整个确认流程。它本身并不关心消息体内的具体内容，也不会执行其中的业务逻辑。执行业务逻辑是消费者（Consumer）的职责。",
    "source": "文档中「消息确认的角色」->「2. RabbitMQ服务器（Broker）」部分",
    "hint": "在生产者、Broker和消费者这三个角色中，哪一个才是真正“处理”消息内容的角色？"
  }
];
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            const errorRate = totalQuestions > 0 ? Math.round((wrongCount / totalQuestions) * 100) : 0;

            const finalScoreHtml =
                '<div class="final-score-container">' +
                '<h2>答题报告</h2>' +
                '<div class="score-summary">' +
                '<div class="score-card">' +
                '<h3>得分</h3>' +
                '<p>' + correctCount + ' / ' + totalQuestions + '</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>正确率</h3>' +
                '<p>' + accuracy + '%</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>错误率</h3>' +
                '<p>' + errorRate + '%</p>' +
                '</div>' +
                '<div class="score-card score-details">' +
                '<table>' +
                '<tr><td>正确</td><td>' + correctCount + '</td></tr>' +
                '<tr><td>错误</td><td>' + wrongCount + '</td></tr>' +
                '<tr><td>未答</td><td>' + skippedCount + '</td></tr>' +
                '</table>' +
                '</div>' +
                '</div>' +
                '<div class="report-actions">' +
                '<button id="review-btn">回顾测验</button>' +
                '<button class="primary" onclick="location.reload()">再试一次</button>' +
                '</div>' +
                '</div>';

            let reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }
            quizContentEl.insertAdjacentHTML('beforeend', finalScoreHtml);
            document.getElementById('review-btn').addEventListener('click', reviewQuiz);
        }

        function reviewQuiz() {
            const reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  